Bioinspired Multi-material Polyjet-printed Frog Robot for Synchronous and Asynchronous Swimming

This paper proposes the bioinspired soft frog robot. All printing technology was used for the fabrication of the robot. Polyjet printing was used to print the front and back limbs, while ultrathin filament was used to print the body of the robot, which makes it a complete soft swimming robot. Dual thrust generation approach has been proposed by embedding the main muscle and antagonistic muscle in all the limbs, which enables it to attain high speed (18 mm/s), significant control to swim in dual mode (synchronous and asynchronous modes). To achieve the swimming motion of frog, four SMA (BMF 300) muscle wires were used. The frog robot is named as (FROBOT). The hind limbs are 60 mm long and 10 mm thick on average, while the front limbs are 35 mm long and 7 mm thick. Model-based design and rigorous analysis of the dynamics of real frogs have allowed FROBOT to be developed to swim at a level that is remarkably consistent with real frogs. Electrical and mechanical characteristics have been performed. In addition, the test data were further processed using TRACKER to analyze angle, displacement and velocity. FROBOT (weighs 65 g) can swim at different controllable frequencies (0.5–2 Hz), can rotate in any direction on command from custom built LabVIEW software allowing it to swim with speed up to 18 mm/s on deep water surface (100 cm) with excellent weight balance.